1. Field of the Invention
The present invention relates to a yarn guide needle for a jacquard knitting machine, and a yarn guide unit for a jacquard knitting machine, capable of being operated by a simple mechanism and of guiding yarns of any types.
2. Description of the Related Art
Knitting machines capable of knitting figured fabrics, such as raschel knitting machines and recent tricot knitting machines, are provided with a jacquard machine for selectively guiding yarns to needles specified according to a desired pattern. FIGS. 5 and 6 show a representative yarn guide unit for a jacquard machine. This yarn guide unit is formed by uniting a yarn guide block a and a plurality of yarn guide needles b and b' provided at their tips with guide holes d and d', respectively, i.e., jacquard reeds. A dropper pin c is brought into contact with a specified one of the yarn guide needles once every one stitching cycle of the needles to control a plurality of yarns individually. Each of the yarn guide needles b and b' is bendable when the dropper pin c is brought into contact with the same. The yarn guide needles b and b' are arranged in a plurality of rows corresponding to the rows of the needles of the knitting machine.
The yarn guide block a is mounted on a yarn guide mount of the knitting machine and is operated by a complex yarn guide operating mechanism for operation to move the yarn guide needles along a rectangular path or a U-shaped path for overlapping and underlapping (hereinafter referred to as "overlapping") operations to wrap the yarns around the needles. While the yarn guide block a is reciprocated transversely through a distance corresponding to the pitch of the needles for an overlapping operation to wrap the yarns around the needles, specified dropper pins c are lowered so as to come into contact with the shoulders e of the corresponding yarn guide needles b and b' by the operation of the jacquard head according to control commands given by the jacquard machine, so that the tips of the yarn guide needles b and b' corresponding to the specified dropper pins c are restrained from movement together with the yarn guide block a by a distance corresponding to the pitch of the needles. Thus, the yarn guide needles b and b' are controlled selectively to control the yarns individually to form a pattern in the fabric.
Since the tips provided with the guide holes d and d' of the specified yarn guide needles b and b' of the yarn guide block a are restrained from transverse movement by bringing the dropper pins c into contact with the shoulders e of the specified yarn guide needles b and b' so that the specified yarn guide needles b and b' are bent, the yarn guide needles b and b' must be formed of a material capable of being elastically bent and of restoring its original shape, such as a spring plate. Smooth, fine yarns pass the guide holes d and d' of the yarn guide needles b and b' substantially without being encountered by resistance and hence a pattern can be formed in the fabric. However, when thick yarns, fuzzy yarns, stretchable yarns or highly taut yarns pass the guide holes d and d', the yarns are encountered by a high resistance and, when the yarn guide block a is driven for instantaneous transverse movement, the yarn guide needles b and b' of an elastic material are restrained from free movement by the yarns. Consequently, the guide holes d and d' cannot be accurately moved to desired positions, a desired pattern cannot be formed and, in the worst case, the yarn guide needles b and b' collide against the corresponding needles to break the needles.
Whereas unfigured portions of the fabric can be knitted simply by instantaneously reciprocating the yarn guide block a, figured portions of the fabric are formed by bringing the dropper pins c into engagement with the specified yarn guide needles b and b' of the yarn guide block a. Therefore, a yarn guide block driving unit for transversely moving the yarn guide block a and a dropper pin driving unit for vertically moving the dropper pins c must be mounted separately on the frame of the knitting machine and hence two driving and controlling systems are necessary, which complicates the construction of the knitting machine and increases the weight of the knitting machine.